Service key



FIG. 1 is a top, front perspective view of a service key showing my new design;

FIG. 2 is a bottom, rear perspective view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a right side elevational view thereof, with the left side elevational view being identical thereto; and,

FIG. 6 is a front elevational view thereof, with the rear elevational view being identical thereto. 

The ornamental design for a service key, as shown and described. 